“Welcome to an evening of divine imbibing and decadence,” said the emcee from a compact, elevated stage in the back of the narrow, crowded bar in Berlin. He wore red-and-black striped pants and had fringes on his jacket’s epaulets, and he introduced Roxy Diamond, a Swiss expat who, working down from a flouncy dress to full burlesque regalia (which is to say minimal regalia), strutted, shimmied and gleefully evoked catcalls.